From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751111AbVJJXiv (ORCPT ); Mon, 10 Oct 2005 19:38:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751177AbVJJXiu (ORCPT ); Mon, 10 Oct 2005 19:38:50 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:47356 "EHLO hermes.mvista.com") by vger.kernel.org with ESMTP id S1751094AbVJJXit (ORCPT ); Mon, 10 Oct 2005 19:38:49 -0400 Subject: Re: [PATCH] ppc highmem fix From: Paolo Galtieri To: Linux Kernel In-Reply-To: <1128986427.16630.6.camel@playin.mvista.com> References: <1128986427.16630.6.camel@playin.mvista.com> Content-Type: text/plain Date: Mon, 10 Oct 2005 16:38:49 -0700 Message-Id: <1128987529.16630.14.camel@playin.mvista.com> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-22) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2005-10-10 at 16:20 -0700, Paolo Galtieri wrote: > I've noticed that the calculations for seg_size and nr_segs in > __dma_sync_page_highmem() (arch/ppc/kernel/dma-mapping.c) are wrong. > The incorrect calculations can result in either an oops or a panic when > running fsck depending on the size of the partition. The problem with > the > seg_size calculation is that it can result in a negative number if size > is offset > size. The problem with the nr_segs caculation is returns > the > wrong number of segments, e.g. it returns 1 when size is 200 and offset > is 4095, when it should return 2 or more. > > Here is the patch to fix the problem. > > --- linux-2.6.14-rc3-git8/arch/ppc/kernel/dma-mapping.c 2005-10-10 > 13:55:37.000000000 -0700 > +++ linux-2.6.14/arch/ppc/kernel/dma-mapping.c 2005-10-10 > 13:57:51.000000000 -0700 > @@ -401,10 +401,10 @@ > static inline void __dma_sync_page_highmem(struct page *page, > unsigned long offset, size_t size, int direction) > { > - size_t seg_size = min((size_t)PAGE_SIZE, size) - offset; > + size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); > size_t cur_size = seg_size; > unsigned long flags, start, seg_offset = offset; > - int nr_segs = PAGE_ALIGN(size + (PAGE_SIZE - offset))/PAGE_SIZE; > + int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; > int seg_nr = 0; > > local_irq_save(flags); > > > Paolo Galtieri (pgaltieri@mvista.com) > I want to apologize in advance for the previous post. When I included the patch inline I dropped the tabs :-(. Here is the correct patch with tabs: --- linux-2.6.14-rc3-git8/arch/ppc/kernel/dma-mapping.c 2005-10-10 13:55:37.000000000 -0700 +++ linux-2.6.14/arch/ppc/kernel/dma-mapping.c 2005-10-10 13:57:51.000000000 -0700 @@ -401,10 +401,10 @@ static inline void __dma_sync_page_highmem(struct page *page, unsigned long offset, size_t size, int direction) { - size_t seg_size = min((size_t)PAGE_SIZE, size) - offset; + size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); size_t cur_size = seg_size; unsigned long flags, start, seg_offset = offset; - int nr_segs = PAGE_ALIGN(size + (PAGE_SIZE - offset))/PAGE_SIZE; + int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; int seg_nr = 0; local_irq_save(flags); Paolo